Unfortunately when the first and second time differ even though identical (recorded) steps were performed, one has to ask the question: why and can I trust it?

My rule of thumb is "search for the problem on Google. If nothing comes up, maybe something is wrong on my end".

Did you find any results or reported bugs similar to what you experienced?

Yes there were other mentions of it with notes to it being fixed in a later systemd drop, which we can't deploy because RH/CentOS don't ship it. I think one of our guys raised a case with RH but I was dragged off onto something else then.

I have my share of reservations about systemd (and PA), but thought that it might be worth pointing out that "known good" hardware A with software X, doesn't have to mean hardware A is all good, just that A has no bugs/errors not exposed when running X. So Y comes along (new kernel, drivers?) with entirely new code - and suddenly things behave erratically.